Laminated core for electrical apparatus



April 9, 1935. w. J. OLEARY' LAMINATED CORE FOR ELECTRIQALAPPARATUSFiled May 16, 1934 INVENTOR.

' latented Apr- UNITED; STATES PATENT Ol-FlCE wmammomn zasqsemw'alslgnortoLuoyB.

' Canada lontreal, Quebec,

, Application in, 1a, 1934, Serial K0315398- 1s Claims. (cl. 155-856) iThe present invention relates broadly to electrical apparatus and moreespecially to laminated cores for transformers, magnets, motors, and

other electrical apparatus .where laminated mag- 5 netizable parts are adesirable feature.

One of the reasons for using a laminated core in electrical apparatus;particularly apparatus for I use with an oscillating or alternatingcurrent is v the prevention of eddy currents which produce 19 electricallosses and heating of the core. A laminated core built up of unpolishedsheets of iron x or iron'alloy results'in a body comprising platessufiiciently insulated from one another to prevent the flow of the weakeddy currents in one plate 5 from continuing through to another plateand so on through the mass. This insulation is probably due to the dime!oxidation which normally occurs on ordinary commercial sheets oi iron oriron alloys which are used in their normal 94) polished condition. Itisnecessary to securely lock the plates together in order to preventsinging or vibration of the plates under the influence of the magneticsurges set up by the oscillating currents when such cores are in use.

'l7he common practice in looking the plates to= gether is to punch ordrill holes through the plates and pass fastening members through theseholes. The holes through the plates leave bright unoxidized metalcomprising the walls of the holes, andin order topreventshort-circuiting oi the plates, because of these bright suriecesthe usual practice has been to surround-the iasteninc members or rivetswith a tube of insulating material, usually rubber or flbre, and toplace washers of rubber or fibre beneath the ends of the rivets orbolts. This construction is expensive, requires careiul assembly, andnecessarily increases the size of the openingsbeyond a size necessaryfor the strength 'of a suitable. fastener.

.4 The present invention overcomes the diificulties of the-known art byproviding a fastener com- F prising a metal member having its surfacetreated with a non-conducting material which is not destroyed by theapplication or the fastener. to the laminated sheets.

The preferred form of. the invention comprises the utilization of ironor iron alloy tubes of the proper length, which are tlicroug oxidizedcntheir surface with the oxide of such a character as to permit the endsof the tubes to be expanded by swat-l Spinn n riveting or other means insuch manner that the tubes become hollow rivets which lock thelaminations tightly together. These hollow tubes may be provided withanopen seam which permits the ends to be riveted without unduestretching of the metahand preferably the tubesare "treated" by aprocess known in the art as parkerizlng, which is the treatment of ironor iron alloy by chemicals to produce an oxidized suriace that verytightly adheres to the metal. This may be accomplished by dippin thetubes or other fasteners into a hot phosphoric acid solution ofmanganese phosphate, or a solution of acid meta-phosphate of tungsten,molybdenum or the like to. produce phosphates of iron on the surface ofthe tube or fastener. This process is in general commercial use and asspecified above is mown as parkerizing.

cases for the purpose specified, has demonstrated conclusively that suchtubes when used as fastening members-for ted cores may be tightlyriveted in place without destroying the insulating coating these tubeshave proved in commercial use to be a complete solution for thedimcuities above outlined in the priornrt. The tube head at the otherend I 1; serticn.

The use of these tubesas fasteners permits the quick, rcpic'l assemblyof laminated. cores without extraordinary care and by the use of machineoperations which avoid the careful manual formed after in essembiyrequiredwhere the washers and 121311-- laminated cores. f

Realizing that the present methods and structures may be carried out andproduced, by meth-'* ads and constructions other than those herewithspecifically disclosed, the disclosure herewith is to be understood asbeingillustrative and not in the limiting sense. c

Fig. l is e perspective view illustrating a tube in accorce withthepresent'invention ready The commercial use of these fastener tubes inelectric motor is preferably provided with e. head on one enrL-the 4 tobebled in a suitable laminated structure.

Fig. 2 is a perspective view illustrating-such tube'in place as asecuring memberfor a laminated structure. j I Referring now moreespecially to the drawing, Fig. 1 illustrates a tube of the preferredform comprising a cylindrical tubular'member, one having a head at I; anopen seam 2 and with the surface 6 thereof comprising a parkerized Fig.2 illustrates a laminated structure showa portion of the structure insection and with the tube in place. This structure comprises a013151310118 d which are provided with an openins through which the tube9 extends and with the ends of the tube 6 being tightly riveted over theend ltions in such manner as to lock i structure tightly together. i The"parkerized surface on the tube is indicated in Fig. 2 by the dottedlines 1.

e iron or iron alloys are referred to in connection with thelaminations, it is to he understood that any material may be utilizedfor the sheets comprising the laminations. It is also to be understoodthat the present invention in its p hav concept comprises the separationof the faste members from the laminated or riveted or-attached by othersecuring means,

such as pins or the like. 7 Having thus described my invention, I herebyc 1. An article of manufacture comprising a rivet formed of a metaltubewith a head fed onone end and provided with a rust-proof insulatmgcoating having a molecular attachment to the said rivet.

2. An article of manufacture comprising a rivet in the form of asplitmetal tube with a head the covered with a rust-proof insulatingcoating having a molecular attachment to the said rivet.

3. An article of manufacture comprising a rivet of a magnetizable metaltube with a head thereon covered with a rust-proof a. l m. coatinghaving a molecular attachment to the said rivet.

d. An article of manufacture comprising 9. fm-

As a for lated cores of electrical apparatus, said fastener comprising amagnetizable metallic member provided with a rust-proof in ting coatinghaving a molecular attacent to the fastener.

I mamas 5. As an article of nufacture, a fastener for laminated cores ofelectrical apparatuasaid fastener comp a metallic body portion'with arust-proof and insulating surface adapted to insulate said fastener fromthe :un 1 tions.

'6. As an article of manufacture, a'fastener for n ted cores of.electrical apparatus, said fastener comprising a magnetizable metal bodycoated with a metallic rust-proofing and insulating layer adapted toinsulate said member from the ltions.

7. As an article of manufacture, a fastener for laminated cores ofelectrical apparatus said fastener comprising a magnetizable metallicbody portion coated with a rust-proofing material comprising a moleculeincluding atoms'of the magnetizahle metal, mid coating being aninsulator of electricity. 1

8. An article of manufacture comprising a fastener for laminations ofcores for electrical apparatus, said fastener comprising a' tubularmember provided with an open seam and coated with insulating material.

9. An article of manufacture comprising a fastener for laminations of alaminated core for electrical apparatus, said fastener comprising aniron tubular member having an open seam and coated with insulatingmaterial comprising a chemical combination of iron and an oxidizer.

it. An article of manufacture comprising a fastener for laminationsof aelectrical apparatus comprising an iron member having a surface thereoftreated to comprise phosphates of iron.

' 11. An article of manufacturecomprising a fastener for Hemof .lated;cores for electrical apparatus comprising an iron fastener having aparkerized surface.

12. a. core for electrical apparatus compris a plurality of supeposedsheets of iron having the surfaces thereof coated with iron omdeend withthrough fasteners passing through said sheets, said fasteners comprisingiron members having parke surfaces.

13. A lated core for elect cal apparatus comp t s superimpmed sheets ofmagnetizable material provided with openings, fasteners era- 30laminated core for

